The present invention relates to a dental handpiece (1; 1 ') which comprises a body (3) intended to be held by an operator, such as a dentist or dental hygienist, an implement (9) being able to be fitted in a front part of the body (3) so that the operator is able to carry out an oral procedure on a patient with the aid of the implement (9) when holding the body, a light source (29) being disposed in the body (3) and intended to emit light for illuminating the patient's oral cavity during the oral procedure. The invention is characterized in that the dental handpiece (1; 1') additionally comprises a lens arrangement (33) designed to diffuse the light from the light source (29) within the patient's oral cavity.